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Wenger A, Schmidt RS, Portmann R, Roetschi A, Eugster E, Weisskopf L, Irmler S. Identification of a species-specific aminotransferase in Pediococcus acidilactici capable of forming α-aminobutyrate. AMB Express 2020; 10:100. [PMID: 32472439 PMCID: PMC7260336 DOI: 10.1186/s13568-020-01034-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/23/2020] [Indexed: 11/19/2022] Open
Abstract
During cheese ripening, the bacterial strain Pediococcus acidilactici FAM18098 produces the non-proteinogenic amino acid, α-aminobutyrate (AABA). The metabolic processes that lead to the biosynthesis of this compound are unknown. In this study, 10 P. acidilactici, including FAM18098 and nine Pediococcus pentosaceus strains, were screened for their ability to produce AABA. All P. acidilactici strains produced AABA, whereas the P. pentosaceus strains did not. The genomes of the pediococcal strains were sequenced and searched for genes encoding aminotransferases to test the hypothesis that AABA could result from the transamination of α-ketobutyrate. A GenBank and KEGG database search revealed the presence of a species-specific aminotransferase in P. acidilactici. The gene was cloned and its gene product was produced as a His-tagged fusion protein in Escherichia coli to determine the substrate specificity of this enzyme. The purified recombinant protein showed aminotransferase activity at pH 5.5. It catalyzed the transfer of the amino group from leucine, methionine, AABA, alanine, cysteine, and phenylalanine to the amino group acceptor α-ketoglutarate. Αlpha-ketobutyrate could replace α-ketoglutarate as an amino group acceptor. In this case, AABA was produced at significantly higher levels than glutamate. The results of this study show that P. acidilactici possesses a novel aminotransferase that might play a role in cheese biochemistry and has the potential to be used in biotechnological processes for the production of AABA.
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Affiliation(s)
- Alexander Wenger
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.,Department of Biology, University of Fribourg, Rue Albert-Gockel 3, 1700, Fribourg, Switzerland
| | - Remo S Schmidt
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
| | - Reto Portmann
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland
| | | | - Elisabeth Eugster
- Bern University of Applied Sciences, School of Agricultural, Forest, and Food Sciences HAFL, Länggasse 85, 3052, Zollikofen, Switzerland
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Rue Albert-Gockel 3, 1700, Fribourg, Switzerland
| | - Stefan Irmler
- Agroscope, Schwarzenburgstrasse 161, 3003, Bern, Switzerland.
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